1. Field of the Invention
The present invention relates to valves, and more particularly to levered valves for draining fluid from a fluid reservoir.
2. Description of the Prior Art
Recommended maintenance for all internal combustion engines includes periodic oil changes. Oil is generally drained from an oil pan upon removal of a standard drain plug, located at the underside of the oil pan. Due to the low clearance created by the placement of the drain plug close to the ground, the oil change procedure can be difficult, messy and time consuming.
There are six factors which are essential for good marketplace acceptance of an oil drain valve, each and every one of which is an object and advantage of the presently described invention. The oil drain valve
(1) must be essentially the same size and shape as a standard drain plug, thereby preventing damage to the valve or oil pan through contact with road hazards;
(2) must minimize the oil residue left remaining in the oil pan, thereby preventing contamination of the new oil;
(3) must maximize the flow of oil, thereby minimizing the time required for an oil change;
(4) must be dependable, thereby preventing inadvertent loss of oil during the operation of the engine;
(5) must provide for convenient operation; and
(6) must be of simple design to facilitate low cost production.
The basic problem in meeting these six objectives is the small size limitation on the drain fitting. A one-piece valve unit necessarily involves either (1) an internal actuating component which would severely restrict the flow, or (2) an external actuating component which would protrude beyond that occupied by a standard drain plug. A two-piece valve unit requires a coupling which is (1) long enough to couple effectively and to fully operate the valve, but (2) short enough to avoid undue interference with the flow. The presently described invention solves this basic problem through the use of a two-piece valve with a mechanically advantaged lever mounted on a removable actuator.
While there are many existing valves which could accomplish one or more of these functions, the lack of marketplace acceptance demonstrates that no prior art has succeeded in meeting all of these criteria. The oil drain valve, Lappier and Formier U.S. Pat. No. 4,745,894 drains most of the oil in the oil pan and is adapted for connection to a hose. However, the valve is inadequate because it extends farther below the oil pan than a standard drain plug, and because the use of a hollow inner rod to conduct the flow of oil substantially reduces the flow of such oil.
Valves designed for other purposes are not readily adapted for use as an oil pan valve. Quick-coupler connectors such as those issued as Ohlsson U.S. Pat. No. 4,208,034 and Johnston and Garcia U.S. Pat. No. 4,660,803, and screw type connectors such as Parker U.S. Pat. No. 2,318,965 are inadequate for three reasons. (1) Such devices lack side holes and therefore would leave a residue of oil in the oil pan, significantly restricting the flow of oil. (2) By placing a male component within the bore of the female component, such devices do not take advantage of the maximum bore of the female component for oil flow. This further inhibits the oil flow. (3) Such devices incorporate a coupling mechanism which requires a greater axial travel than is acceptable in a devise as small as an oil drain valve.
Other valves are even less adequate. A beer-key tapping valve, as outlined in Haag U.S. Pat. No. 3,302,660, is inadequate because the valve is designed to be placed perpendicular to the bottom of a fluid container, and would not operate effectively when inserted into the bottom of an oil pan. Fluid sampling valves, as typified by Hargrove U.S. Pat. No. 4,699,356, are inadequate because they are larger than a standard drain plug, and because they would significantly restricts the flow of oil. A standard piston valve adapted to oil pan usage by the inclusion of perpendicular inlet and outlet openings, as typified by Ketchpel U.S. Pat. No. 2,669,414, is inadequate because either the handle would extend from the bottom of the oil pan, or it would have to be operated from within the oil pan. A pipe tapping valve typified by True U.S. Pat. No. 3,721,259, is inadequate because it is unnecessarily large and complex.